Selective Liquid Phase Hydrogenation of Benzaldehyde to Benzyl Alcohol Over Alumina Supported Gold

Abstract We report for the first time 100% benzyl alcohol yield from the liquid phase ( T = 353 K, P = 9 bar) hydrogenation of benzaldehyde over Au/Al 2 O 3 . Under the same reaction conditions, a benchmark Pt/Al 2 O 3 catalyst promoted the formation of toluene and benzene as hydrogenolysis by-products. Reaction kinetics was subjected to a Hammett treatment and the reaction constant ( ρ = 0.9) was found to be consistent with a nucleophilic mechanism. A solvent (alcohol, water and alcohol + water) effect is demonstrated and ascribed to competitive adsorption where solvation by polar (water) facilitates benzaldehyde activation. Graphic Abstract